They have pitched poorly enough that they may not opt out of their contracts or – if they do make themselves free agents – would have teams wondering about their skills. Not long ago, this looked like a strong starting-pitching market approaching in 2017-18, fronted by that duo plus Jake Arrieta, Yu Darvish and, to a lesser extent, Chris Tillman.

All but Darvish, however, have pitched well below their peaks this season, and even for Darvish, the combination of age (31 in August), Tommy John surgery in March 2015 and the worst homer and strikeout rates of his career, with a rise in walk rate, might give teams pause in just how far they will go.

Now, some provisos:

1. All teams must contemplate how much the record homer frenzy is hurting pitching stats. Even top starters are being overwhelmed by the long ball – Clayton Kershaw, for example, already has yielded a career high in homers. Tanaka is giving up one homer for every four fly balls yielded — the 25 percent rate is the worst since at least 2002 (via Fangraphs). Teams might spend more on starters if they think this is just bad luck or if they think some kind of reversal is coming because – perhaps – the ball is more lively than ever and will be deadened some again.

2. Pitching is always in demand and the sport is financially healthy, so money will be spent. Tanaka, who has the majors’ third-worst qualified ERA (6.34), would have to walk away from $67 million over three years. Cueto, whose 4.42 ERA is his worst since he was a rookie in 2008, would have to walk away from $87 million over four years. But if Jeff Samardzija two offseasons ago could get $90 million – albeit over five years – could Tanaka and Cueto top that based on track record alone?

Yankees starting pitcher Michael PinedaEPA

Obviously, what happens hereafter matters. These are the free-agent starters I find most compelling to track for what it could mean this offseason:

1. Michael Pineda

He mainly has stayed healthy now for three straight years. He is still just 28. He has great stuff and is having a strong walk year (he starts Tuesday night). Teams could look at starters with stuff – such as A.J. Burnett and especially Ivan Nova – who left The Bronx (both to the Pirates) and got better and think the same could be coming for Pineda. You can argue his overall body of work/stuff as a starter is better than Samardzija’s when Samardzija became a free agent.

2. Jason Vargas

He has the slowest average fastball (85.9 mph) in the majors, excluding knuckleballer R.A. Dickey and 40-year-old Bronson Arroyo. Yet, the Royals lefty is one of the few starters defying the spike in homers with just six allowed in 87 1/3 innings – three of which have come in 10 innings against the Yankees. In his first full season back from Tommy John surgery, he has a 2.27 ERA.

3. Arrieta

At this time last year, he seemed headed for $150 million-plus. His agent, Scott Boras, has insisted the Cubs righty remains elite because of his track record. However, Arrieta recently told MLB Network’s Ken Rosenthal a heavy workload (468 1/3 innings the past two years, including the postseason) has affected his stuff. His average fastball velocity is down 2.5 mph from his 2015 Cy Young season while his ERA has climbed from 1.77 in 2015 to 3.10 to 4.64 this season. Like Darvish, Arrieta already is 31.

Tyler ChatwoodAP

4. Tyler Chatwood

The Rockies righty leads the majors in walks, and in the past two years since returning from Tommy John surgery has a 3.95 ERA with just 6.9 strikeouts per nine innings – the 10th lowest among 57 pitchers who have made 40 starts. So why is he here? First, he is just 27. Second, there is no more Jekyll and Hyde starter depending on locale: His 6.21 ERA at home at Coors Field the past two years is the second worst in the majors (minimum 15 starts). His 1.97 ERA on the road is the best, ahead of Kershaw (2.21) in second and Darvish (2.45) in third. Will teams believe away from the high altitude, they can get a top starter?

5. Tyson Ross

This is a wild card in a class that – among others – will include Alex Cobb, Marco Estrada, Jaime Garcia, Jeremy Hellickson, CC Sabathia and John Lackey. Ross made one start last year (on Opening Day) and has made one this year (last Friday). In between, he had surgery for thoracic outlet syndrome, and as we have seen with Matt Harvey, the return from that operation follows no set path. The Rangers gambled a $6 million guarantee they could get Ross healthy and pitching like he did for the Padres in 2014-15, when he had a 3.03 ERA (albeit in a pitching favorable home park).